[R] Odp: adding column of ordered numbers to matrix

From: Petr PIKAL <petr.pikal_at_precheza.cz>
Date: Thu, 10 Jun 2010 18:02:17 +0200

Hi

r-help-bounces_at_r-project.org napsal dne 10.06.2010 15:56:06:

> Hello everyone,
>
> I have a matrix of over 40000 line and about 30 columns.

Matrix or data.frame?

>
> For my analysis I would like to add another column with ascending
numbers
> (column header should be "order", and than 1,2,3,4 ....the end of the
> matrix).

If data frame DF

DF$order <- 1:nrow(DF)

in case of matrix mat
mat <- cbind(mat, "order"=1:nrow(mat))

Regards
Petr

PS. order is built in function so it is not especially wise to use it as a name for some object/column

> During my analysis I reorder them ( due to merge commands by a different
> column).
>
> How do I add such a column in an ascending order (or descending for what
it
> matters)?
>
> THX
>
> Assa
>
> [[alternative HTML version deleted]]
>
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https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. Received on Thu 10 Jun 2010 - 16:04:35 GMT

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